What Is Glaucoma?

How glaucoma affects a person's eyes

Glaucoma is the second-leading cause of blindness in the world, and it's six times more likely to occur in those over the age of 60. If someone close to you is diagnosed with glaucoma and it's left untreated, it could lead to tunnel vision or even blindness. Here's what you need to know about the disease and how to help the person cope.

Also know that early diagnosis and treatment can preserve a person's vision.

What's the cause of glaucoma?

If someone has glaucoma, it means that his optic nerve -- which carries images from the eye to the brain -- has been damaged. This is often the result of a buildup of fluid and pressure in the eye (known as intraocular pressure, or IOP), but scientists are also researching other causes, because people without elevated eye pressure also get glaucoma. Glaucoma can develop in both eyes or in only one eye. The more damage to the optic nerve, the more significant the vision loss.

The two main kinds of glaucoma

The first type is chronic, or open-angle, glaucoma, and the second type is acute, or angle-closure, glaucoma.

  • Chronic glaucoma is the most common form, and it also advances more slowly and is easier to treat. It develops as the eye's drainage canals become clogged, resulting in a rise in inner eye pressure. It can cause a gradual, sometimes imperceptible, loss of sight over the course of years.
  • Acute glaucoma results in a faster rise in eye pressure and more quickly advancing symptoms. In this case, the outer edge of the iris covers the drainage canals and blocks the fluid from draining. When this occurs, it's considered a medical emergency: The patient should see an eye doctor right away to prevent further vision loss. Signs that he may be having an acute glaucoma attack: severe eye pain (chronic glaucoma usually isn't painful), headaches, blurry vision, nausea, and vomiting.
  • There's also a condition called secondary glaucoma, which means that something else (like another disease, a medication, or an injury) is causing increased eye pressure and damaging the optic nerve.

To see a picture of the eye and read about how eye drainage works, visit the Glaucoma Foundation's website .

Risk factors and effects of glaucoma

The seven main risk factors for glaucoma
  • Genetics Chronic glaucoma is hereditary. If someone on a person's side of the family has glaucoma, it increases his risk four to nine times.
  • Age Those over age 60 are six times more likely to get glaucoma than those under 60.
  • Health conditions Problems like diabetes and hypertension can affect eye pressure and contribute to glaucoma.
  • Certain eye conditions Severe nearsightedness (myopia) and central corn eal thickness of less than .5 mm are thought to be risk factors for glaucoma.
  • Race The leading cause of blindness among African Americans, glaucoma is five times more common in African Americans than in Caucasians. Hispanics over the age of 60 are also at higher risk than those of European ancestry over the age of 60. And those of Asian heritage seem to be at higher risk for acute glaucoma.
  • Steroids Very high steroid levels (which might be found, for instance, in someone who uses steroids to control severe asthma) may increase the risk of chronic glaucoma.
  • Eye injury An injury can damage the eye's drainage system. Sports-related injuries like those incurred in boxing or baseball are most often to blame.
What does the world look like for someone with glaucoma?

If the person you're concerned about is in the early stages of glaucoma, he may have no symptoms at all. In fact, experts believe that half of those with the disease don't know they have it.

When symptoms do occur, a person may at first notice a loss of peripheral (side) vision, as nerve fibers on the outer edges of his field of vision become damaged. He may even turn his head to the side to see. At some point he may see halos around lights and notice a loss of contrast between objects -- making it easy for him to miss a step and tough for him to drive, especially at night.

As the glaucoma progresses, his field of vision may narrow, as if he's looking through a tunnel. Eventually, if his glaucoma goes untreated, he may lose his vision entirely.

Treatment for glaucoma

There's no cure for glaucoma, but there are ways to control it. And because the vision loss it causes is irreversible, you'll want to make sure the glaucoma is caught early on and monitored for the rest of the life of the person you're caring for.

Treatment options include medication like eyedrops or pills to control eye pressure (by slowing or improving the drainage of fluid, for example), laser treatment, or surgery.

Chronic glaucoma, in particular, responds well to medication. But some of these drugs have many possible side effects, so talk with the eye doctor and make sure the patient knows what to expect and what to report to the doctor after he starts taking the medication. Also, sometimes a prescription dosage will need to be adjusted or a different medication substituted over time. Again, monitoring is crucial.

Laser treatment is sometimes used when glaucoma doesn't respond to medication. A small scar is made in the eye's drainage system, allowing fluid to flow more freely out of the eye. In more severe cases, a surgical procedure called filtering microsurgery is used to create a small drainage hole.

Some studies have suggested that it's possible to reduce eye pressure with regular exercise. In one study, glaucoma patients exercised for three months -- riding stationary bikes four times per week for 40 minutes -- and reduced their IOPs an average of 20 percent. But talk with the eye doctor about the effects of exercise on his glaucoma: Exercise may not be helpful for everyone, and for some people it may even result in an increase in IOP.

To learn more about glaucoma treatment, you may want to sign up for the Glaucoma Foundation's free booklets and newsletter.

Karen Miles

Karen Miles is a regular contributor to numerous national magazines, including Woman's Day , Reader's Digest , Family Life , Family Circle , and Better Homes & Gardens , as well as to the award-winning website BabyCenter. See full bio